1. Technical Field
The disclosure relates to a light sensing circuit, a liquid crystal display having the same, and a method of driving the same. More particularly, the disclosure relates to a light sensing circuit to detect external illuminance, a liquid crystal display having the same, and a method of driving the same.
2. Discussion of Related Art
Liquid crystal displays (LCDs) have been extensively used due to their superior image quality, lightness, slimness and low power consumption. Since an LCD is a non-emissive display apparatus, a light source, such as a backlight unit, is necessary.
A white light emitting diode (LED) may be used as a backlight unit in a small-sized or medium-sized display apparatus. A cold cathode fluorescent lamp (CCFL) may be used as a backlight unit in a large-sized display apparatus, such as a laptop computer.
The backlight unit can consume a majority of the power in an LCD. Power consumption can be reduced in a backlight unit of an LCD by use of a sensor. For example, a sensor may be attached to an outer portion of an LCD to detect peripheral illuminance, and a sensing circuit can then be used to convert an analog signal detected from the sensor into a digital signal to control brightness of the backlight unit by using the digital signal.
However, the output value of the sensor may vary under the same peripheral luminance due to deviation between sensors. The sensing circuit may be provided with a calibration circuit to calibrate the deviation between sensors. However, since the internal structure of conventional sensing circuits are complicated, the manufacturing cost of the LCD is increased.
The conventional sensor and the sensing circuit may be fabricated separately from the manufacturing process for an LCD panel and attached to an outer portion of the LCD panel when the LCD panel is assembled as a product. However, fabricating the sensor and the sensing circuit separately can increase the manufacturing time and the manufacturing cost for the LCD.
Thus, there is a need for a light sensing circuit capable of obtaining the same digital output value under the same peripheral luminance regardless of deviation between sensors, an LCD having the light sensing circuit, and a method of driving the light sensing circuit.